The present invention relates to a new and improved construction of a high-voltage circuit breaker or switch.
Generally speaking, the high-voltage circuit breaker or switch of the present development is of the type comprising at least one primary switch position with which there is connected in parallel a series circuit of an auxiliary switch position provided with a cut-on or switching-in resistor, Both switch positions are operatively coupled, by means of a respective lever drive, with a drive rod which is movable between a cut-on position and a cut-off position. As to these lever drives the lever drive operatively correlated to the primary switch position contains a double-arm lever which is pivotable about a stationarily arranged shaft. One end of this double-arm lever is coupled with the drive rod and the other end of such double-arm lever is coupled with the movable switching element of the primary switching location. The lever drive operatively correlated with the auxiliary switch position is structured such that during a cut-on stroke there is initially closed the auxiliary switch position and such again opens at the end of such cut-on stroke.
With high-voltage circuit breakers or switches, wherein a series circuit of an auxiliary switch position equipped with a cut-on resistor is connected in parallel with the primary switch position, the auxiliary switch position, during a cut-on stroke, closes before the primary switch position for the purpose of switching-in the cut-on resistor. With high-voltage circuit breakers or switches of this type, two species or classifications of such circuit breakers are to be distinguished from one another. With the first species the auxiliary switch position is reopened shortly after the primary switch position has been closed, i.e. at the end of the cut-on stroke. With the second species the auxiliary switch position remains closed even when the primary switch position is closed, and measures are taken which, during a cut-off stroke, cause the auxiliary switch position to open before the primary switch position. The high-voltage circuit breaker or switch disclosed according to the present invention belongs to the first species or class described above.
With a prior art high-voltage circuit breaker or switch of this type, as known to the art from German Pat. No. 2,108,915 and the corresponding U.S. Pat. No. 3,763,340, granted Oct. 2, 1973, the course of the movements accompanying the cut-on stroke and characteristic for the here discussed species of circuit breaker, are obtained by facilities which are complicated and, therefore, in practice, have proven not to be very functionally reliable. With this prior art high-voltage circuit breaker or switch the movable switching element of the auxiliary switch position is operatively associated with a spring-force storage which must be tensioned during a cut-on stroke. This initially requires a higher drive output or power. The spring-force storage is blocked by means of a locking element until there has been reached the cut-on position of the primary switch position. Upon reaching the cut-on position the locking element is displaced and the spring-force storage is released, whereby there is retracted the switching element of the auxiliary switch position. During the course of the cut-off stroke the locking element, which is exposed to the action of a spring, again assumes its blocking or locking position. If, with this prior art high-voltage circuit breaker, the locking element should become jammed for any possible reason, whether it be in the blocking position or in the release position, then there is no longer guaranteed for the desired mode of operation of the circuit breaker.
With a further high-voltage circuit breaker or switch of the initially mentioned type and not belonging to the present state of the art, it has been proposed, by specially designing the lever drive correlated to the movable switching element of the auxiliary switch position, to construct an arm of an angle lever leading to the drive rod as one of the two members of a toggle lever which can be pressed-over and whose other member is hinged to the drive rod. In the case of a toggle lever which can be pressed-over one of the members of the toggle lever, which member is hinged to a respective one of the three hinges of the toggle lever, necessarily must be displaceable thereat in a translatory fashion with respect to the corresponding pivot bolt, for instance by means of a longitudinal slot or hole. As a result, there does not exist a coupling which is free of play between the drive rod and the movable switching element of the auxiliary switch position and, consequently, the lever drive is exposed to considerable shocks which occur during a switching operation.